1. Field
This application relates generally to a touch-sensitive surface for creating or modifying a computer-generated image, and more specifically to a touch-sensitive surface adapted to reduce user-generated and/or device-generated input errors.
2. Related Art
In traditional animation, drawings are first drawn onto paper, and photographs of the drawings are taken and used as frames that form an animation film, in contrast, in computer animation, drawings are often drawn directly into a computing system. Computer input devices, such as touch-sensitive drawing surfaces and styluses, have taken on many of the functionalities that were traditionally provided by paper and pen.
FIG. 1 shows an exemplary drawing table 100 that can be used to create or modify a computer-generated image. Drawing table 100 includes touch-sensitive surface 110 that is arranged in close proximity with display 120. A user may interact with the displayed compute-generated image by moving a touch object, such as stylus 130, on touch-sensitive surface 110. Drawing table 100 tracks the positioning of stylus 130 across touch-sensitive surface 110.
Touch-sensitive surface 110 may be susceptible to user-generated and/or device-generated input errors. Jitters are one form of input errors. Jitters may be user-generated or device-generated. For example, if a user shakes his hand while he is drawing with stylus 130, drawing table 100 may perceive the shaking movement as input jitters that are then reflected in the computer-generated image being drawn. These jitters are considered to be user-generated. As another example, if an electronic component that is nearby touch-sensitive surface 110 generates electrical noise, touch-sensitive surface 110 may perceive the electrical noise as jitters that also become reflected in the computer-generated image being drawn. These jitters are considered to be device-generated. User imprecision is another form of input errors. For apparent biological reasons, rapid human hand movements tend to be imprecise, thus, a human user tends to trade precision for speed while using computer input devices (e.g., a stylus). User imprecision are also reflected in the computer-generated image being drawn.
These input errors are undesirable because they impact the ability of drawing table 100 to interpret user input accurately. Further, these input errors are especially acute for touch-sensitive surfaces that have relatively high precision, but relatively low accuracy, such as recent market offerings that support 600±DPI (dots-per-inch) input precision.